[Task]: remove `default` as the default parent project

### What needs to happen?

if the `HOP_CONFIG_FOLDER` environment variable is not set, `default` is used as the default parent project when creating new projects.
This causes quite a bit of confusion. Users should have the option to create a new project with a parent project, but shouldn't be forced to.

When `HOP_CONFIG_FOLDER` is set, there is no parent project set by default, so this doesn't apply in that scenario.

### Issue Priority

Priority: 3

### Issue Component

Component: Other

Locate the code that reads HOP_CONFIG_FOLDER and assigns the default parent project during new project creation. Compare behavior with and without that environment variable, then verify that new projects have no parent by default while still allowing users to select one.

Written by the indexing model from the issue text.